Some medical devices used to resect tissue have a tube-in-tube construction. In such a construction, an inner tube is disposed within an outer tube, and the tubes are designed to rotate relative to one another (for example, the inner tube is designed to rotate while the outer tube remains stationary). In some designs, the proximal end of both the inner and the outer tube can include cutting edges between which the tissue is disposed and sheared. In other designs, the proximal end of the inner tube can include a burr that shears the tissue.